In a conveying system, storage units are often utilized to balance the flow of articles in the conveying system. For example, if a stoppage or slow-down occurs downstream in the conveying system, the articles can be stored or accumulated in a storage unit and when the slowdown has ceased, the stored articles are automatically fed back into the conveyor system.
U.S. patent application Ser. No. 06/669,625, filed Nov. 8, 1984, now U.S. Pat. No. 4,609,091 discloses a storage unit for a conveying system which comprises a series of parallel secondary conveyors that extend laterally from a side edge of a main conveyor. When it is desired to store articles, a stop is moved to an obstructing position above the main conveyor to stop a row or train or articles. The row of articles is then transferred laterally from the main conveyor to the secondary conveyors and the row is conveyed on the secondary conveyors to a stopped position. Successive rows are similarly transferred from the main conveyor to the secondary conveyors.
As disclosed in the aforementioned patent application, when the secondary conveyors are filled with a plurality of rows of articles, lift members are elevated between the spaced secondary conveyors to lift the articles to a storage location.
Subsequently, when it is desired to return the articles to the conveying system, the rows of articles are lowered onto the secondary conveyors and are conveyed back to the main conveyor. As the first row is returned to the main conveyor, the secondary conveyors are momentarily reversed in direction of movement to separate the first row from the remaining rows.
As disclosed in the above-mentioned patent application, to insure complete return of the articles in a row to the main conveyor, positioning members are located between adjacent secondary conveyor and as the remaining rows are separated from the first row, the positioning members are elevated, causing inclined surfaces on the positioning members to engage the trailing edge of each article in the row and urge the articles onto the main conveyor.